Hello, new to the forum, and the .450BM. I just put together my first .450BM upper, using all Franklin Armory parts minus the upper receiver and bolt carrier (those are both Colt).
After opening up the ejection port opening on my upper receiver to accommodate the .450BM case, I noticed that the bolt would not go into battery, which appears to be due to the extractor not wanting to slip over the case rim. No matter how hard I "sling shot" the charging handle, it will not slip over the case rim. Pushing the forward assist helped nothing.
So, I was hoping some of you fine folks could take a close-up photo of your .450BM bolt face (with the extractor installed) so I can compare them to mine? The only way we could get the upper to hand cycle properly (feeding and extracting/ejecting like it should) was to shim the extractor about ~.030". To us, it looked as though the extractor claw was too far inside the bolt face circle (if that makes sense), so the extractor was just pushing against the bottom of the case rim, rather than pushing and slipping over it. Shimming the extractor out allowed it to slip over the case rim, and still extract the case fine by hand, cycling the rifle using the charging handle (with the firing pin removed for safety).
I'm trying to determine if I have an out or spec bolt, extractor, etc. BTW, after reading a long post from Hoot, I measured the cases on my new Hornady Black ammo, and they are measure about .470" and .400" (versus .473" and .409").
Any help is greatly appreciated!
Blessings,